Inter-vertebral disc prosthesis with variable rotational stop and methods of use

摘要

A prosthesis is adapted for implantation into the spine. The prosthesis has a first member and a second member. The first member and the second member have a permitted range of rotational motion with respect to one another. The amount of permitted rotation of the first member relative to the second member is dependant on the extent of flexion and extension of the spine.